Literature Review on Health and Fatigue Issues Associated with Commercial Motor Vehicle Driver Hours of Work (2005) / Chapter Skim
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Part I General Literature Review
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Responding to that lawsuit, in July 2004, the U.S. Court of Appeals for the Washington, D.C., Circuit ruled that DOT's FMCSA did not follow a congressional mandate to consider truck drivers' health in the revised HOS rules.
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The purpose of the literature review was to provide information that clearly discusses in a scientific, experimental, quantitative, or qualitative way, the relationship between the hours a person works or the structure of the work schedule (e.g., on-duty/off-duty cycles, sleep time, etc.) and the impact on some medical conditions of concern to truck drivers.
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and a Certified Professional Ergonomist (CPE) • Recognized authority on sustained performance of aviators, heavy equipment operators, and of CMV driver fatigue, factors relating to driver wellness and health, and occupational and environmental medicine research • Co-investigator on two truck driver simulator studies and one large field study on CMV truck driver alertness and fatigue issues • Principal developer of two FMCSA and American Trucking Associations' (ATA)
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• 30 years experience in measurement of human performance, and human factors consulting, specializing in driver behavior, transportation safety, and shift work • Senior specialist in assessment of work-rest schedules, shift work, hours of work and worker rest for transportation industries (railways, coast guard and marine vessels, trucking, etc.) and for nuclear power plant and manufacturing operations • Project manager for several Transport Canada projects involving literature review and development of experimental protocols related to fatigue and minimum recovery periods for CMV drivers • Forensic consultant with expertise on car and truck driver fatigue and shiftscheduling issues • Consultant to both Canadian and U.S.
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– President and Chief Scientist, Alertness Solutions, Cupertino, California – Served as Research Scientist and Team Leader, Fatigue Countermeasures Program, Aviation Safety Research Branch, Flight Management and Human Factors Division, NASA Ames Research Center • Richard Hanowski, PhD. – Leader, Truck and Bus Safety Group, Virginia Tech Transportation Institute – Experience includes transportation human factors with both heavy and light vehicles, laboratory and field testing, real-time automobile and heavy vehicle simulation, advanced system development and testing, design guideline development, and human performance evaluation ORGANIZATION AND PRESENTATION OF PART I: GENERAL LITERATURE REVIEW The literature review is presented in two sections: Health and Fatigue.
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• Lung cancer is likely caused by exposure to diesel exhaust and the longer that exposure lasts the more likely it is that a cancer will develop. Though the evidence linking this exposure to bladder cancer is less robust than that to lung cancer, it remains likely that there is such a relationship and that it is governed by a positive doseresponse curve.
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A search for articles after 1975 was performed on the database using the following terms: Health effects and the following • Commercial vehicle operator • Commercial driver • Driver occupation • Vibration and motor vehicle Based on the results from these searches, each of the search terms -- motor vehicle operator, truck driver, occupation -- was entered with the following: • Bladder cancer • Lung cancer • Cardiovascular disease • Myocardial infarction • Spermatogenesis • Low back pain • Musculoskeletal disorder • Kidney • Renal cancer • Hypertension Each of the search terms -- work hours, shift work, sleep schedule -- was entered with the following: • Gastrointestinal • Diabetes • Glycemic control • Lipid • Cholesterol • Obesity • Mental health • Depression • Peripheral neuropathy • Neurologic disorder • Reproductive • Fertility • Spontaneous abortion • Musculoskeletal disorders In addition, the following was searched: • Swing shift work and health • Rotating shift and health • Sleep cycle and health SELECTION CRITERIA Primary Sources The initial search resulted in more than 1,850 articles. When deemed appropriate by title, the abstracts were reviewed for relevance to the topics of CMV operator health and the health effects of work hours, shift work, and sleep schedule.
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. Finally, a meta-analysis of 29 studies addressing occupational exposure to diesel exhaust and lung cancer showed that 21 of the 23 studies meeting the inclusion criteria observed relative risk estimates greater than one.
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A questionnaire survey of Japanese truck drivers found short resting time and irregular duty time to be significant risk factors for LBP. It also found positive but insignificant associations with long driving time in a day and in a week but the hours were not quantified (Miyamoto 2000)
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disorders then those on a delayed rotating system. Authors concluded that the combination of direction of rotation and length of break when changing from one shift to another may be a critical factor in the health and well-being of shift workers.
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Working Conditions (Environmental except sleeper berth) Odds ratios were adjusted for smoking and asbestos exposure and showed that professional drivers had significantly higher rates of lung cancer.
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412) Though retrospective with estimated exposures, this study, with a large sample population, showed significant associations between lung cancer and both exposure to diesel exhaust and a dose-response.
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Analyses by duration of employment were carried out and interactions with smoking were examined. Results: Male tractor-trailer truck drivers had an elevated risk for bladder cancer (OR = 2.4, CI = 1.4–4.1)
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765) This study was chosen from several that have shown significant odds ratios for bladder cancer in truck drivers (see secondary references)
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. Relative risks for cancers in occupations Primary Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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Relative risks for all six types of cancer were greater than 1. Regarding dose-response, this was a negative study except for the interesting association between ovarian cancer and high cumulative exposure to diesel exhaust.
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Reviewer: CompleteTitle: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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Author's conclusion: "The study showed that high working hours a day and high working hours a week generally went together with a higher need for recovery, confirming our hypothesis that day workers with many working hours a week report more need for recovery from work compared to employees working less hours a week. Extension of the working day, in terms of overtime work, was particularly associated with more need for recovery in both men and women." (p.
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Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references) : Reviewer's Notes:
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Longterm exposure to vibration (equal to the vibration exposure over years in the profession) 22 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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11 of 16) Because this study did not elaborate on sampling and recruiting methods, it is difficult to judge its validity; however, results show that long-term exposure to vibration was a significant risk factor for LBP.
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These results are not specific to truck drivers. 24 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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To evaluate the noise exposure of truck drivers under normal operating conditions. 135 long-haul samples, 66 pick-up and delivery samples, and 29 sleeper berth samples Long-haul drivers n/a Working Conditions (Environmental except sleeper berth)
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The questionnaire itself was reviewed by several experts and verified by extensive job observations of the truck driving task. The finalized questionnaire was distributed to 80 truck drivers, and the answers were used to compile a final list of hearing-critical truck driving tasks, as well as a list of mechanical problems which can be detected through the use of hearing.
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Doses were also measured for nine sleeper berths. In order to determine whether truck drivers experience a temporary decrement in hearing after a normal driving shift (known as temporary threshold shift or TTS)
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Single drivers who spend sleeping time in the sleeper berth with the engine idling or shut off should not experience excessive noise doses in contemporary cabs, because the engine idle SPL is significantly less than the highway speed SPL. There were significantly higher thresholds for these 30 drivers (as compared with the nonnoise exposed population data)
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This is a negative retrospective study of lung cancer risk and exposure to diesel exhaust with study limitations of power, healthy worker, and survivor effects rendering the result of interest but limited weight in rejecting a hypothesis of a causal connection between lung cancer and diesel exhaust. Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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. Logistic regression for lung cancer and cumulative exposure showed that models with 30 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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228) This study used a large cohort as well as state-of-the-art exposure assessment methods to show both increased risk for lung cancer with exposure to diesel exhaust and a doseresponse trend.
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32 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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33 "Woman and men working >71 hr per week had the highest percentage of subfecundity both among first pregnancies and the total sample, and shift work had a similar distribution of subfecundity in both groups for both men and women." (p.
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"These results show that there is a good reason to be concerned about the possible detrimental effects of long work hours on health, in particular cardiovascular disease, diabetes, illnesses leading to disability retirement, subjectively reported physical ill health, and subjective fatigue." 34 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references) : Reviewer's Notes:
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Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references) : Reviewer's Notes:
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595) 36 Primary Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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37 "Findings from the current study suggest that time of work (day vs. evening)
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29 studies on bladder cancer and exposure to diesel exhaust Truck drivers, no further characterization Working Conditions (Environmental except sleeper berth) Fifteen results were available for truck drivers.
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. Hence it can still be concluded that here is probably an association between WBV and LBP," ( but not causalReviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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ity) "Existing knowledge yields sufficient reasons for reducing exposure to the lowest possible level." (p.
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Almost all men in occupations involving professional driving had a statistically significant elevated risk of being hospitalized with prolapsed cervical intervertebral disc. An objective prospective study identifying professional driving as a risk factor for the development of prolapse of a cervical intervertebral disc.
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There was a significantly increased relative risk of MI with high or intermediate exposure to combustion products, (besides motor 42 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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(See Tables 2 and 4.) "We found some indications of an increased risk of MI in association with exposure to motor exhaust, but no firm evidence of an exposure-response relation." The results are suggestive of increasing MI risk with cumulative exposure to motor exhaust.
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The public health impact of work-related knee pain among professional drivers could be substantial." Agree with previous quote. 44 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references) : Reviewer's Notes:
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Results showed that insulin resistance indeed worsened with a longer sleep-wake cycle but was independent of changes in the internal clock or circadian rhythm. 46 Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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1064-65) Reviewer: Complete Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Directly Related to HOS (include page references)
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1066) This chapter, with 166 references, confirms the multiple health issues related to shift work and rotating shift work including GI, cardiovascular, and reproductive health.
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The literature indicates lung cancer is likely caused by exposures to diesel exhaust and the longer that exposure lasts the more likely it is that a cancer will develop. Though the evidence for exposure as a truck driver causing bladder cancer is less robust than that for cancer of the lung, it remains likely that there is such a relationship and that it is governed by a positive dose-response curve.
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"An epidemiologic study of occupational low back pain in truck drivers." J Nippon Med Sch.
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and Minkova, N.K. "Circadian Rhythms of Arterial Pressure, Heart Rate and Oral Temperature in Truck Drivers." Occ Med.
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– HOS regulations – schedules, shift rotation, multi-day shifts – operational and performance models – alertness, fatigue – distraction and reaction time • Drivers and fatigue • Drivers, fatigue, and the following – Driving performance – Driving hours – Length of sleep time, sleep deprivation – Shift work – Sleep deprivation countermeasure (including naps) – Alertness, fatigue – Distraction and reaction time • CMV operators and – HOS – Hours of work – Work rest schedules – Workload – Sleep schedules – Rest periods – Performance (as opposed to ‘"driving performance")
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Federal Motor Carrier Safety Administration. "Impact of sleeper berth usage on driver fatigue." (2002)
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. "The impact of work practices on fatigue in long distance truck drivers." Accident Analysis & Prevention, Vol.
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1,249 truck drivers; 84 management representatives Heavy road transport industry Study relies on driver's memories of their sleep and work activities as well as fatigue levels rather than objective measures. As a definition for fatigue was not provided for drivers or company representatives it is difficult to know how participants were interpreting this concept.
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In addition, it is possible that regulated drivers experience more fatigue because of long driving hours and less discretion to rest, than do the unregulated drivers. However, the authors caution that, in comparing the two studies, one must bear in mind that each asked different questions of drivers' perceptions of fatigue and provided different response options.
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This paper summarizes the results of a survey of truck driver fatigue in New Zealand. Interviews and performance tests were collected from truck drivers at various locations throughout the North Island of New Zealand throughout the day and night.
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= 8.42, P < 0.01. Drivers with an average daily route of fewer than 250 km and drivers 37 years and older were much more likely to fail the performance test." The authors noted that at this stage it was unclear "how to interpret the route length and age effects in the TOPS results." Driver Fatigue/Alertness p.
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determine the effects of four sleep/wake schedules on alertness and performance and (2) develop an algorithmic model to predict performance on the basis of prior sleep parameters." Historical and methodological overview of sleep and performance, description of sleep/ performance model, field study using actigraphs, laboratory study of effect of sleep restriction on performance.
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daily sleep bouts for short-haul drivers were initiated between 2000 and 0200. Sleep bouts initiated at these times lasted longer (i.e., clustered between 6 and 10 hr)
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Some showed a pattern that suggested chronic sleep restriction with intermittent bouts of extended recovery sleep. The authors felt that this suggested that although work-rest schedules could be devised to help minimize CMV driver sleep debt, optimal enhancement of driver alertness and performance would require additional and imaginative approaches.
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ES-5, Field Study: "Time off-duty was positively correlated with total sleep time for both groups, but the short-haul drivers were more likely to consolidate their daily sleep into a single, work-shift sleep period." p. ES-5, Field Study: "Long-haul drivers obtained almost half of their daily sleep during work-shift hours (mainly sleeper-berth time)
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. This decrement was maintained across the entire 7 consecutive days of sleep restriction, suggesting that there was no compensatory or adaptive response to even this mild degree of sleep loss." p.
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Field Study: Long-haul truck drivers operated heavy trucks for a minimum of 6 continuous days, with the typical run being 7 to 10 working days, on their regularly assigned route. Data collection systems were installed on the tractors used by the drivers to collect sleeper-berth environmental data, driving performance information, video of the driver's face, and subjective alertness ratings and data from the Nightcap sleep system.
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. Single drivers "tended to show fewer extreme fatigue-related critical incidents during the morning hours, with gradually more critical incidents being attributed to the very drowsy categories during the evening and nighttime hours." The authors note that single drivers "were exhibiting signs of extreme fatigue during all hours of the day while team drivers only showed signs of fatigue during the nighttime and morning hours." 5.
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of "extreme drowsiness," with most of these instances being experienced by single drivers, again with a high rate of the occurrence of this level of fatigue on the second or third shift after the first day of a multi-day drive. Thus it appears that the combination of long driving times and multiple days provides the greatest concern, with several results pointing to the presence of cumulative fatigue.
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In contrast, where fatigue was allowed to build-up, such as on single trips and on very long two-up trips without stationary rest, breaks did not provide relief once fatigue had accumulated." Driver Fatigue/Alertness p. 550, "Overall, the heart rate measures confirmed earlier findings that single drivers were more alert than two-up drivers at the start of the trip." Reviewers: Title: Abstract: Methodology: Scope of Work: Sample Size: Industry Sector: Major Limitations: Findings Findings Directly Related to HOS (include page references)
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552, "Overnight stationary rest for two-up drivers at mid trip, was associated with dramatic reductions in fatigue levels after the break, and allowed these drivers to finish the trip with the lowest levels of fatigue of any group, including single drivers." p. 552 "Two-up drivers who had no stationary rest, but had the shortest trip duration of any group, showed an overall increase in alertness over the homeward journey, finishing the trip at roughly pre trip fatigue levels." Driver Duration p.
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This paper summarizes a study comparing daytime and nighttime performance of professional drivers on a simulated driving task. The authors noted that to their knowledge no studies had been conducted reporting on the effects of sleepiness on night driving performance in a dynamic truck simulator using professional drivers as subjects.
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70 Findings Directly Related to HOS (include page references)
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The questionnaire contained questions on individual characteristics, their preceding 3 months' work, possible sleepiness-related problems at work and their opinions about maximum permitted driving times. In addition, they were also given parts of the Basic Nordic Sleep Questionnaire and the Epworth Sleepiness Scale to estimate the "prevalence of suspected sleep apnea syndrome and to collect data of driver's sleep history." Drivers were also asked questions about their self-perceived general health status and the occurrence of any chronic illnesses.
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After all, frequent sleepiness-related problems were substantially more common among drivers with the combination of no more than a satisfactory health, prolonged driving, as well as sleep deficit. Notably, frequent difficulties in remaining alert and dozing off had occurred in more than one half of these drivers whereas in only approximately 10% of those drivers with a driving time of at most 10 hr, no sleep deficit, and at least a good health.
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. when all the relevant factors were controlled, shift type and driving time were the only work-related variables that significantly predicted more frequent difficulties in remaining alert (p < .05 and p < .05, respectively)
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Physiological measures included indications of sleep quantity and quality as collected by wrist activity monitors. In addition the "black box" data collection equipment installed in the truck collected driver performance associated with "critical incidents," (i.e., near-crash events)
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Drivers in the fatigue group spent more hours driving during the day of the critical incident as compared with drivers in the no-fatigue group. Driver Fatigue/Alertness p.
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across the industry. This was followed by a driving simulator study which investigated "fatigue-related decline in driving performance resulting from loading and unloading cargo," "non-duty time (rest and recovery)
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(Note: Authors did not describe which types of roads were used in testing.) Driving runs were conducted using 12 preset scenarios, each consisting of a fixed route designed to take approximately 90 min to complete at the posted speed limits.
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because the cumulative effects for each are confounded." However, what can be said about cumulative effects is that they "appear to be nil for practical measures (e.g., probe scores) and mild for parallel subjective measures such as subjective sleepiness." Duty-day subjective sleepiness, reaction time response, and measures of driving performance showed a slight but statistically significant deterioration over the driving week, but driver response in crash-likely situations did not show cumulative deterioration.
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While there was an increase in measured sleep and a decrease in sleep latency on the first off-duty rest day following the end of the driving week, the authors do not believe that the peak sleep periods during the "weekend" days were due principally to sleep deprivation. They noted that drivers varied in the number of hours of sleep per night, and in a by-case examination of driver sleep patterns did not show a higher rebound for those who slept less during the driving week, indicating that the variation observed did not represent deprivation.
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and mild for parallel subjective measures such as subjective sleepiness." p. 3, FHWA-MCRT-99-008, "Drivers returned to baseline reaction time performance and alertness within 24 hours after the end of a driving week, as shown by sleep latency, reaction time testing, and driver rating of subjective sleepiness.
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Proposition 1 specified that fatigue inducing factors would account for variation in these outcome measures. Proposition 2 specified that "company safety management practices should account for variation in the outcome measures, controlling for fatigue-inducing factors associated with truck driving work." Proposition 3 contended that "fatigue while driving accounts for variation in the frequency of close calls due to fatigue and crash involvement, after controlling for fatigue-inducing factors and company safety management practices." Survey conducted with CMV drivers.
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66, "Proposition 3 asserted that fatigue while driving accounts for variation in the frequency of close calls due to fatigue and crash involvement, after controlling for fatigueinducing factors and company safety management practices .
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While close calls ("near accidents") are often used as proxies for crashes, these findings indicate that each outcome has unique antecedents and thus may require different explanations (e.g., percent of time spent loading was observed to be a good predictor of crashes but not related to fatigue or close calls.")
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In addition, their finding that pre-trip level of fatigue appears to be an important determinant of later fatigue raises questions about the ongoing work schedules under which long distance drivers operate, "and highlights the need to allow adequate rest and recuperation between trips and between blocks of trips to prevent chronic sleep loss and to reduce fatigue." Professional truck drivers completed a 12 hr, 900 km trip under each of three driving regimes -- a relay (staged) trip, a working hours regulated one-way (single)
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Pre-trip level of fatigue appears to be an important determinant of later fatigue. This raises questions about the ongoing work schedules under which long distance drivers operate, "and highlights the need to allow adequate rest and recuperation between trips and between blocks of trips to prevent chronic sleep loss and to reduce fatigue." Driver Fatigue/Alertness p.
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The first step in this project involved a comparison of performance on a "range of performance tests under conditions in which study participants should be tired, with performance under conditions in which they had been exposed to varying doses of alcohol" to identify measures that have demonstrated sensitivity for detecting fatigue. Performance tests were administered at regular intervals over time with increasing sleep deprivation (i.e., participants were kept awake a total of 28 hr)
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20, "Evaluation of the current working hours regime suggests that provided drivers are rested to begin with, one full cycle of the regulated regime does not produce fatigue or performance capacity decrements that are of concern for safety. There is considerable evidence however that performance decrements increase significantly as the schedule becomes Industry Sector: Major Limitations: Findings Findings Directly Related to HOS (include page references)
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The results show clearly that it is possible to increase trip length to 16 hours, say, and still maintain good performance levels. It is not possible, however, to continue to do 16 hour trips without a longer break than is usually allowed, even in the regulated regime." p.
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, driving speed and distance monitoring, performance on surrogate tests (i.e., code substitution, critical tracking test, simple response vigilance test) , continuous video monitoring, physiological measures as well as driver-supplied information (e.g., daily logs, Stanford Sleepiness Scale rating)
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Although disruption of circadian rhythms and cumulative fatigue probably contributed, time of day appeared to be a major factor." 90 Findings Findings Directly Related to HOS (include page references)
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91 Driver Duration p. ES-9, "Hours of driving (time-on-task)
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Fatigue-inducing factors, especially insufficient recovery, are statistically associated with a driver experiencing fatigue and close calls due to fatigue (Morrow and Crum 2004)
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This paper presents recent research on compliance with current driving hours regulations, the effectiveness of using driving hours to predict fatigue, and alternative compliance and enforcement options. The paper describes results of a major survey of truck driver fatigue in New Zealand, a review of international compliance and enforcement procedures, and research focusing on the social forces and influences that affect truck drivers.
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Using a portable driving simulator installed in a caravan, volunteer truck drivers are asked to complete a brief survey (about their driving hours and their amount of sleep in the past 48 hr, how sleepiness affects them, and the level of fatigue they feel at that moment) , and go for a "drive" on the driving simulator (measuring their vehicle control and reaction times)
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While there is no single solution to the fatigue problem, much can be done to address driver fatigue through a combination of innovative HOS regulation and enforcement, education, driver work scheduling, innovative fatigue management programs, driver screening, fitness for duty and alertness monitoring systems, and additional research. For the covering abstract of this conference, see IRRD number 872978.
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This experiment addresses the effects of loading and unloading on driving performance by measuring driving impairment in volunteer truck drivers operating a truck-driving simulator. Ten drivers participated, each for 17 days, including 2 driving weeks of 5 days with 14-hr duty cycles separated by two 58-hr rest periods.
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for a 5-day week did not appear to produce significant cumulative fatigue over the 2-week testing period. The drivers returned to baseline levels of reaction time, driving simulator performance, and alertness within 24 hr of recovery time after the end of a driving week as shown by sleep latency, reaction time testing, and driver rating of subjective sleepiness.
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TP 13237E. The purpose of this study was to assess the relationships between prevalence of driver drowsiness observed on a trip, length of prior principal sleep periods, and naps taken during the trip, based on the data collected from actual revenue runs of the Driver Fatigue and Alertness Study (DFAS)
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For the amount of sleep and the 4 to 5 days of driving observed for each driver in this study, it was found that the strongest and most consistent factor influencing driver fatigue and alertness was time of day; drowsiness, as observed in video recordings of the driver's face, was markedly greater during night driving than during daytime driving. The number of hours of driving (time on task)
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The 3-hr afternoon nap increased the subjects' nighttime alertness and improved driving performance. Beneficial effects of the afternoon nap on nighttime driving performance included significantly fewer crashes, shorter run completion times, and smaller standard deviations of lane position.
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Currently, in a government-funded project, TARS researchers are employing advanced driving simulator techniques and instrumented vehicles in order to develop human factors models characterizing driving performance and decisionmaking in various driving situations. Fatigue and Fitness for Duty in New Zealand Truck Drivers is another current project funded by Road Safety Trust.
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The group agreed on the following principles for designing better regulations: provision for minimum sleep periods, the opportunity for sleep and time of day influences; taking account of the cumulative nature of fatigue and sleep loss; taking account of the effect of night work on driving performance and both quality and quantify of sleep; taking account of duration of working time; and provision of short breaks within working time.
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It was decided to use this information to carry out a study on the risk of crash with respect to driving hours and other time intervals related to the drivers' working lives. In the study, a case group of heavy vehicles involved in crashes (for which details of drivers' hours were known from their log books)
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SB: IRRD-OECD. TI: The interaction of mild obstructive sleep apnea, sleep deprivation, and circadian factors in driving risk.
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Location: Tampa, Florida. Sponsored by: American Trucking Associations, Association of American Railroads, Federal Highway Administration, Federal Railroad Administration, National Highway Traffic Safety Administration, and National Transportation Safety Board.
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For the covering abstract, see ITRD E113725. AN: E113860 Janssen, W
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The driving performance of 17 sleepdeprived heavy-truck drivers was monitored on a closed track. Functions in the time, frequency, and phase domains were developed to quantify changes in steering wheel input.
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SB: TRB-TRIS. TI: Circadian Alertness Simulator for Fatigue Risk Assessment in Transportation: Application to Reduce Frequency and Severity of Truck Accidents.
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"Effects of partial and total sleep deprivation on driving performance." (1999)
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The research project addressed the prevalence of sleep apnea among CMV drivers, potential risk factors, and its impact on driving performance. This tech brief summarizes the project's final report, "A Study of Prevalence of Sleep Apnea Among Commercial Truck Drivers." AN: 00932082 Stutts, J.C., Wilkins, J.W., and Vaughn, B.V.
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AB: This tech brief summarizes an Intelligent Transportation System (ITS) study titled "Evaluation of Techniques for Ocular Measurement as an Index of Fatigue and as the Basis for Alertness Management." The study was funded in part by the FHWA's Office of Motor Carriers and managed by the National Highway Traffic Safety Administration (NHTSA)
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PY: 1999. AB: In a driving simulator, the effects of time on task were measured on variables that measure drowsiness, driving performance, and steering behavior for groups of younger and older drivers.
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The study was conducted in the laboratory. Twenty long-haul truck drivers and 19 people not employed as professional drivers acted as subjects.
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Sleep deprivation countermeasures, e.g., naps (13) Hours-of-service regulations: general considerations, schedules, shift rotation, multi-day shifts, outcomes of pilot tests and waivers, operational and performance models (14)
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Is there any scientific literature that addresses specifically the relationship between number of driving hours above a certain threshold and operator's fatigue?
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